1. Field of the Invention
The present invention relates to a handle attachment structure for rotatably attaching a handle to a casing, and a projector provided with the handle attachment structure.
2. Description of the Related Art
Conventionally, a projector for modulating a light beam irradiated from a light source in accordance with image information to form an optical image and to enlarge and project the optical image has been used.
Such projector and other electronic devices have a casing for accommodating an optical lens, an electronic component and other components. Some of the casings are provided with a handle (grip) for enhancing portability thereof.
The handle is generally formed in C-shape and both ends thereof are rotatably supported to the casing through a shaft member.
The casing of projector and other electronic devices are often made of plastics because of processibility. Inside of such plastic-made casing is plated.
Since effective utilization of resources has come to be required recently, it is preferable that the electronic devices including projector are made of recyclable material.
Accordingly, instead of the composite material of plastics and inner plating, the casing may be formed by recyclable metal.
In order to form the component by the metal material, the thin sheet metal plate working is conducted by a press etc. or, alternatively, molten metal is injected by die-casting molding.
When the casing is shaped by a press using a metal plate of a predetermined thickness, the component can be inexpensively manufactured as compared to die-casting because a metal plate is used, and since the component is simply processed using a press die, yield rate of the component can be improved. Accordingly, the casing is preferably shaped by sheet metal working.
However, since the casing is made of thin metal plate and a shaft member is attached thereto in attaching a handle to the casing made of sheet metal, the attachment work may not be conducted easily and appearance after attachment is not so good because the inside of the casing is seen from a gap between the casing and the handle.
An object of the present invention is to provide a handle attachment structure and a projector capable of easily attaching the handle to the casing with good appearance in forming the casing by a sheet metal.
A handle attachment structure according to the present invention is for rotatably attaching a handle to a metal casing formed by sheet metal working, which includes: a cut-out portion formed by cutting a part of the casing; a rising portion formed by drawing or bending the casing toward the inside of the casing along the cut periphery of the cut-out portion; a shaft member inserted to an attachment hole formed on the rising portion for rotatably supporting the handle; and a screening member engaged to the rising portion for covering the cut-out portion from the inside of the casing.
According to the present invention, the cut-out portion is formed on the casing by sheet metal working, the rising portion is formed along the cut periphery of the cut-out portion and the attachment hole is formed on the rising portion. The shaft member having attached with the handle is inserted to the attachment hole.
Since the inside of the casing can be seen from the gap between the handle and the rising portion in this condition, the screening member is engaged to the rising portion to close the gap by the screening member.
Accordingly, in the present invention, the handle attachment portion can be easily formed on the metal casing by sheet metal working and the handle can be easily attached to the casing through the shaft member. Further, since the cut-out portion is covered by the screening member from the inside of the casing, the inside of the device cannot be seen from the cut-out portion, thus improving the appearance after attaching the handle.
In the present invention, the shaft member may preferably be made of metal and include a rotation restricting mechanism for restricting a rotation of the shaft member.
Since both of the shaft member and the casing are made of metal, frictional sound is caused by rubbing the metal components when the shaft member rotates relative to the casing. However, according to the above arrangement of the present invention, since the rotation of the shaft member relative to the casing can be prevented by the rotation restricting mechanism, the frictional sound can be prevented from generating. Further, shaky movement of the shaft member relative to the casing in accordance with friction can also be prevented.
In the present invention, the rotation restricting mechanism may preferably include a flat surface formed on an end of the shaft member and a contact surface formed on the screening member to be in contact with the flat surface for restricting the rotation of the shaft member.
According to the above arrangement, the flat surface can be easily formed by squashing or grinding the end of the shaft member. Since the contact surface to be in contact with the flat surface is formed on the screening member, extra components can be omitted to simplify the structure of the rotation restricting mechanism.
In the present invention, the screening member may preferably be provided with an insert hole for the shaft member to be inserted and a fall-off preventing member for preventing the shaft member from dropping off the insert hole.
According to the above arrangement of the present invention, since the shaft member does not erroneously drop off from the insert hole of the screening member on account of the fall-off preventing member, the screening member is not detached from the rising portion.
In the present invention, the fall-off preventing member may preferably include a flexible member being in contact with axial end surface of the shaft member and deforming toward outside in radial direction when the shaft member is attached.
According to the above arrangement, the shaft member is attached when the screening member is attached to the rising portion of the casing and, simultaneous with attaching the shaft member, the fall-off preventing member is also attached. In other words, two originally independent works can be conducted by attaching the shaft member, thereby improving productivity.
In the present invention, the flat surface of the shaft member may preferably be formed by squashing the distal end of the shaft member to be larger than the shaft diameter thereof, and the fall-off preventing member may preferably include a position restricting surface to be in contact with the end surface of the distal end of the shaft formed with the flat surface.
According to the above arrangement of the present invention, since the flat surface restricts in a direction for the shaft member to enter the insert hole and the position restricting surface restricts in a direction for the shaft member go out of the insert hole, the structure of the screening member can be simplified.
In the present invention, an air intake hole for introducing cooling air into the casing may preferably be provided to the screening member.
For accommodating a heat-generating electric device such as a light in the casing, the inside of the casing has to be cooled. However, since the air intake hole is formed on the screening member in the above arrangement, the cooling air can be introduced to the inside of the casing through the air intake hole even without cooling air introducing hole is not formed on the casing.
The outer surfaces of the handle and the casing may preferably be respectively coated and a projecting step portion projecting toward outer direction relative to the coated surface and having no coating may preferably be formed on at least one of the handle and a portion of the casing to be engaged to the handle.
According to the above arrangement, since the handle and the casing are coated, durability can be improved. Further, since the projecting step portion is formed on at least one of the handle and the casing, on the handle for instance, sound generated by rubbing the coated surfaces of the casing and the handle can be prevented.
A projector may be constructed including the handle attachment structure of the above-described arrangement.
According to the above aspect of the present invention, a projector capable of easily attaching the handle to the casing with good appearance can be provided.